What you have now should be plenty ,if you just want to go to one card then I would go with a GTX-670 since it just a hair slower then the GTX-680 and will use less power then one HD6970, over a 100watts less at maximum.Plus it will have plenty of power for B.F.3 at max details at 1920 x1080.Plus it runs very quiet.The Gigabyte or the ASUS IMONVIDIA GeForce GTX 670 2 GB Review | techPowerUp